The proper treatment of contaminated water has become more and more important as the number of toxic and biologically recalcitrant organic compounds have increased in water. Commonly known systems are sequentially coupled, in that they involve a two-step process of advanced oxidation followed by biodegradation. In other words, sequentially coupled systems have chemical and biological treatment processes in separate stages.
In the ideal case of sequential coupling, advanced oxidation is controlled so that the recalcitrant organic compounds are only transformed to the point that they are rapidly biodegradable, at which point they would be passed to the biodegradation stage. Chemical transformation beyond this point generally wastes oxidant and increases operation costs with no further benefit. Because advanced oxidants are indiscriminate and fast acting, they produce a large range of products including those that are too oxidized, may be toxic themselves, or may be unavailable for biodegradation. If a large number of biodegradable compounds are present in the water in comparison to the number of recalcitrant compounds, much of the oxidant will be spent on already biodegradable organics and result in inefficient water treatment. In current systems, bacteria effective for biodegrading the biodegradable organics cannot be in proximity to the AOP, because the reactants used in advanced oxidation are severely toxic to bacteria. Thus, current systems do not allow for intimate coupling of AOP and biodegradation for at least the aforementioned reasons.
Thus, there is a need in the art for systems and methods for efficiently treating contaminated water using an intimately coupled advanced oxidation and biodegradation process that maintains the integrity of the necessary compounds used in these processes.